Auto-discovery and management of base station neighbors in wireless networks

ABSTRACT

Systems and methods are disclosed that include determining a local node configuration for a local network node. The local network node configuration can include a local range and a local location. In addition, these systems and methods can include receiving a remote network node configuration for a remote network node via a communications link. The remote network node configuration can include a remote range and a remote location. Also these systems and methods can further include generating a neighbor list that includes the remote network node and the local network node. The neighbor list can be determined using the local network node configuration and the remote network node configuration.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 USC 119(e) to U.S. ProvisionalApplication Ser. No. 60/954,895, filed on Aug. 9, 2007, which isincorporated herein by reference.

TECHNICAL FIELD

The present invention relates generally to wireless communicationsystems, and more particularly to a network architecture and methods forbase station neighbor automatic discovery (identification or learning),configuration and/or dynamic tuning to optimize network performance.

BACKGROUND

Some of the most challenging and costly tasks undertaken by networkoperators when introducing new telecommunications infrastructure oradding capacity to existing infrastructure (such as adding access points(“APs” or base transceiver stations (“BTSs”, also referred to herein as“base stations”)) includes network planning, development and operationalefforts. The efforts to setup and optimize such networks are significantand traditionally necessitate lengthy periods until attainment of anoptimum and stable system. This is usually done based on initial, manualconfiguration of the BTSs at the time of deployment.

Base station neighbor information is critical for wireless networkoperation, for such information is utilized by base stations, networkcontrollers and access service network (“ASN”) gateways (depending uponnetwork architecture) for various applications, including Radio ResourceManagement (RRM), neighbor BTS communication associated with handoffs(handovers), and multi-step paging based on BTS neighbor topology. Thisneighbor information is also crucial to the successful operation ofemerging, high data rate 4G wireless systems, such as those built (or tobe built) in conformance with wireless specifications such as LTE (LongTerm Evolution) promulgated by 3GPP (Third Generation PartnershipProject) and that promulgated by the Worldwide Interoperability forMicrowave Access Forum (WiMAX) for interface auto discovery. This WiMAXspecification is also known as the Institute of Electrical andElectronic Engineers (IEEE) 802.16e-2005 standard, and is incorporatedherein by reference.

Access points and base transceiver stations provide users (and theircommunications devices known as “subscriber stations”) wirelessconnectivity to wireless access service networks (ASN). These accesspoints have different names depending upon network architecture and thestandard to which the network is constructed, but they generally sharesimilar characteristics, such as antenna(s) and base stationtransceiver(s). In cellular deployments, the antennas are mounted tophysical structures, such as towers, buildings and other generallyelevated structures. Once connected to the ASN, users have the abilityto move about the ASN, with their call sessions (data or voice) beingtransferred as necessary from one base station to another. Within thenetwork, each BTS is connected (via wireless or wireline) to acontroller node. The controller node can be in the form of a “gateway”(GW) generally responsible for controlling and communicating with anumber of BTSs. Such gateways can be connected to a global network,which can be the public switched telephone network (“PSTN”), Internet,or other wired or wireless communications network. It is critical forwireless network operators to ensure that call sessions maintaincontinuity as these call sessions are handed off from one BTS toanother. As noted above, network operators typically populate lists ofBTS neighbors at the time of network turn-up, but such manualconfiguration fails to take into account the inherently dynamic natureof networks, as planned (and unplanned) BTS service outages arise, orBTSs otherwise fully operational become unavailable for relatively shortperiods of time due to operation at capacities that inhibitparticipation in call handoffs, as can occur incident to activities suchas large gatherings (e.g., major sporting and theatrical/musicalevents), or extraordinary events (accidents on highways, etc.).

Deployment and functioning of emerging 4G wireless technologies, such asLTE and WiMAX face many of the challenges existing in cellular/PCSnetworks. However, some of these challenges are more pronounced in theseemerging 4G technologies as a consequence of their deployment, in manyinstances, at higher frequency bands (1.5 GHz to 11 GHz). One of theproblems impacting such deployments concerns “shadowing”, a phenomenoninvolving diffraction around obstacles (such as buildings, water towers,etc.). Such diffraction becomes more problematic at higher frequencies,as the signal wavelength correspondingly diminishes. Moreover, atelevated frequencies (and depending upon prevailing RF conditions), lineof sight (LOS) between the BTS and the subscriber terminal can becomemore of an issue. While urban areas are places where high data rateswould be beneficial, these urban areas also exacerbate the LOS problem(e.g., buildings, obstacles, etc). Some locations will have no LOS,while other locations will have acceptable LOS in the vicinity of thecell site (BTS location), with poor LOS in areas further from the cellsite. The 4G wireless technologies are designed for high data rates.Typically, high data rates can only be achieved with highsignal-to-noise ratios (SNRs). Because LOS is not possible (or limited)in many locations, many subscriber stations are severely impacted inlocations resulting in no LOS with low SNR. Often a subscriber stationbehind an obstacle may acquire the network (i.e., the control channelcan be detected), but data throughput rates are low. A high number ofusers will be in disadvantaged locations that will not support high datarates between the subscriber station and BTS. Therefore, combating theshadow/LOS problem is a major issue in the deployment and operation ofemerging 4G wireless technologies at higher frequencies in urban anddense urban areas.

Accordingly, there are needed infrastructure components and methods thatprovide self-configuration and self-optimization solutions for automaticdiscovery (identification or learning) of BTS neighbors (and BTSneighbor information) to avoid the individual and manual provisioning ofneighbors on each BTS and controller. Such is desirable in instances ofinitial network deployment, capacity enhancements (such as arise fromthe addition of further BTSs), service outages and restarts, and othersuch situations that impact the network. Further, as operatingconditions change in the network due to operation limitations asdescribed above, it is important to be able to dynamically tune (i.e.,identify) the list of neighbor BTSs available for handoff communicationswhen the network conditions change (e.g., signal degradation due toshadowing (i.e., signal degradation due to physical obstructions in thepath between the servicing BTS and the user, limitations in theavailable line of sight to the user, changes in BTS range, etc.).

SUMMARY

In accordance with one embodiment, a method is disclosed that includesdetermining a local node configuration for a local network node. Thelocal network node configuration can include a local range and a locallocation. In addition, this method can include receiving via acommunications link a remote network node configuration for a remotenetwork node. The remote network node configuration can include a remoterange and a remote location. Also this method can further includegenerating a neighbor list that includes the remote network node and thelocal network node. The neighbor list can be determined using the localnetwork node configuration and the remote network node configuration.

In accordance with another embodiment, a method is disclosed thatincludes obtaining a first information about a first base station. Thefirst information can include location and range information relating tothe first base station. This method includes sending the firstinformation to a first server. Also disclosed in this embodiment isobtaining a second information about a second base station. The secondinformation comprises location and range information relating to thesecond base station. In addition, this method includes sending thesecond information about the second base station to the server,generating a neighbor list from the first information and the secondinformation, and transmitting the neighbor list to the first basestation and the second base station.

In yet another embodiment, a system is disclosed that includes a firstbase station. The first base station is capable of storing firstidentification information relating to the range of the first basestation and the location of the first base station and communicatingwith a first network. This system may also include a second base stationthat is capable of storing second identification information relating tothe range of the second base station and the location of the second basestation. The second base station is also capable of communication with asecond network. Thus system may further include a server that is capableof communication with the first network and the second network. Theserver is capable of receiving the first and second identificationinformation, creating a neighbor list based upon the first and thesecond identification information, and transmitting the neighbor list tothe first base station and the second base station.

Other technical features may be readily apparent to one skilled in theart from the following figures, descriptions, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, wherein likenumbers designate like objects, and in which:

FIG. 1 depicts a high level diagram of an example diagram with aplurality of BTSs and ASNs within an illustrative (such as WiMAX)wireless communications network, in accordance with one embodiment ofthe present disclosure;

FIG. 2 is a block diagram of a system used within a ASN shown in FIG. 1,in accordance with one embodiment of the present disclosure;

FIG. 3 is a reference diagram of a BTS, according to one of thedisclosed embodiments, in accordance with one embodiment of the presentdisclosure;

FIG. 4 is a reference diagram of the messages transmitted between BTSstations and ASNs shown in FIG. 1, in accordance with one embodiment ofthe present disclosure;

FIG. 5 is an illustration of informational elements used in determininga list of neighbor BTS, in accordance with one embodiment of the presentdisclosure;

FIG. 6 depicts one method of implementing the disclosed embodiments;

FIG. 7 depicts ranges of various BTSs used to create a list of BTSneighbors, according to one of the disclosed embodiments;

FIG. 8 is an illustration of the coverage angle of a BTS, according toone of the disclosed embodiments;

FIG. 9 is an example of the coverage area between two neighbors,according to one of the disclosed embodiments; and

FIG. 10 depicts priority messages based upon a neighbor list.

DETAILED DESCRIPTION

FIG. 1 illustrates an example of a communications network architectureor system 100 in accordance with the present disclosure. The network orsystem 100 shown in FIG. 1 is for illustration purposes only, andrepresents a plurality of cells or sectors. Other embodiments of thesystem 100, constructed in conformance of any of a multitude ofstandards, may be used without departing from the scope of thisdisclosure. Reference to “standards” as used herein is meant toencompass existing and future versions of the referenced standards, aswell as standards encompassing the principles of the subject matterdisclosed and claimed herein.

In this example, the system 100 is part of a larger access servicesnetwork (not shown), and the system 100 includes a base station (BTS)112, a BTS 114 and a BTS 116 each communicating with an access servicenetwork (ASN) 102. Also shown in system 100 are a BTS 106, a BTS 108 anda BTS 110 each communicating with an ASN 104. The ASN 102 communicateswith the ASN 104 (via wireless or wireline communications). Included asa part of each ASN 102, 104 is one or more BTS controllers, in the formof gateways or servers 120 (FIG. 1 illustrates gateways X1 through X3within ASN 102 and Y1 through Y3 within ASN 104).

One problem prevalent in wireless communications, irrespective of theprotocol or standard upon which it is based, is that when acommunication device (such as a subscriber station, also referred to asa mobile station) moves from one area to another area, the signalstrength may vary and ultimately may decline to a level insufficient tomaintain communications or, in any event, high data rates. Even when amobile station is within the theoretical range of one BTS, physicalobstacles or other conditions may inhibit communication with the BTS. Insuch a case, communications may be disrupted or lost. In response tomovement outside the BTS coverage area or when other factors inhibit orreduce reliability of communications with the BTS, the BTS (or network)may initiate a communications handoff from the servicing BTS to anotherBTS to improve the communications link to the communications device.This necessarily requires knowledge of the BTS's neighbors.

As described above, the identification and provisioning of each BTS'sneighbors within the system is usually performed manually within eachBTS and/or the ASNs at the time of initial network setup or when aresource is added to, or removed from, the existing network. This manualprovisioning is time-consuming, expensive and relatively static. Inaddition, network operating conditions (e.g., coverage range of a basestation, which is based on various factors) may change substantiallyover time and as a result, coverage area of a given BTS may be differentthan that relied upon when the BTS neighbors were initially provisionedfor each BTS. Therefore, those BTSs identified as neighbors for a givenBTS may not truly be neighbors and problems with handoffs may occur.

One disclosed method (or methods) to overcome these problems is the useof automatically discovered and/or dynamically updated neighborrelations to configure the system 100. A neighbor's relation 118 isshown as a box that illustrates that the BTS 112 and the BTS 110 areneighbors. Details as to the manner by which automatic discovery isimplemented are provided in the below specification. The automaticallydiscovered and dynamically updated relations promote automaticconfiguration and optimization of the network 100. For instance, trafficamong a plurality of mobile stations (MS) can be balanced among aplurality of BTSs. Moreover, signal loss or interruptions may beanticipated based upon empirical signal conditions to promote a handofffrom one BTS to another BTS prior to the detection of a signal loss.Network operating conditions can be measured periodically to provide forgeneration of an updated neighbor list for a given BTS, thus allowingfor a high degree of dynamic BTS neighbor tuning and/or optimization.These, and other innovative and unique aspects of the presentdisclosure, will be discussed in more detail below.

The ASN 102 and the ASN 104 may include one or more local area networks(“LAN”), metropolitan area networks (“MAN”), wide area networks (“WAN”),all or portions of a global network, or any other communication systemor systems at one or more locations, or combination of these, includingthe public switched telephone network (PSTN), Internet, packet networksand the like. The ASN typically also includes a BTS backhaul network(not shown) which is a data network utilized for communications betweenthe BTSs and ASNs. These networks may be configured to include Internet,packet networks and the like. In one embodiment, the ASNs 102, 104 (orportions thereof) are Internet Protocol (IP) based networks, and inanother specific embodiment, the system or network 100 operates inaccordance with the WiMAX standard (IEEE 802.16). It is understood thatone or more servers (not shown) may communicate through the ASN 102 andthe ASN 104.

Other components, devices or networks may be included in the system 100,and FIG. 1 only illustrates but one exemplary configuration to assist indescribing the system and operation to those skilled in the art. Thesystem 100 represented in FIG. 1 may be described using differentnomenclature or system terminology, such as use of the terms accessterminal (AT) or mobile subscriber terminals (MS or MT) or subscriberstations (SS), base station (BS) or base transceiver station (BTS) (aswell as Node B, enhanced Node B and so forth), and the use of any givennomenclature to describe a device within the system 100 is not intendedto limit the scope of this disclosure. As will be understood by thoseskilled in the art, air interface technologies utilized by BTSs in thesystem 100 may encompass technologies or standards such as, by way ofnon-limiting example, 2G, 2.5G, 3G, GSM, IMT-2000, UMTS, iDEN, GPRS,1×EV-DO, EDGE, DECT, PDC, TDMA, FDMA, CDMA, W-CDMA, LTE, TD-CDMA,TD-SCDMA, GMSK, OFDM, WiMAX, the family of IEEE 802.11 standards, thefamily of IEEE 802.16 standards, IEEE 802.20, etc. For example, theWiMAX standard defines two network architectures or modes:point-to-multipoint (PMP) mode and mesh mode. In the PMP mode, everysubscriber station directly communicates with a BTS and may indirectlycommunicate with another subscriber station but only through a BTSfirst. This network mode has a star structure with the BTS at the centerof the star. In the mesh mode, every subscriber station is operable todirectly communicate with every other subscriber station—the BTS is notrequired. The architecture illustrated in FIG. 1 implements the PMPmode, as subscriber stations receive instructions from the BTS unit theyare communicating with. However, it is expressly understood that theinnovative elements of the present disclosure could be implemented ineither a PMP mode or other modes and, as noted previously, the teachingsof the present invention are independent of air interface standard andtechnology.

The BTSs (e.g., 106, 108, 110, 112, 114, 116) have coupled thereto oneor more subscriber stations (not shown). The subscriber stations areoperable for communicating wirelessly with (or to) the BTSs over an airinterface. In the system 100, any number of subscriber stations may bepresent up to the capacity of the network. Each subscriber stationwithin the system 100 may be fixed or mobile (including nomadic)communication devices. It is to be understood for the purpose of thisdetailed description that subscriber station data ratetransmission/reception is not limited to any specific rate and thatmobility of mobile subscriber stations is not limited to any specificrate of movement.

A conventional BTS generally includes various components such asprocessing units, controllers and network interfaces, which necessarilyinclude but are not limited to, microprocessors, microcontrollers,memory devices, and/or logic circuitry, and these may be adapted toimplement various algorithms and/or protocols. No additional descriptionof the conventional components and software processes (functionality) ofa BTS, other than as noted herein or relevant for an understanding ofthe present disclosure, is provided, as these are known to those ofordinary skill in the art. It will be understood that the BTSs may beconstructed or configured from any suitable hardware, software,firmware, or combination thereof for providing the functionality knownto those of ordinary skill in the art. The BTSs will include additionalfunctionality as described below in accordance with one or moreembodiments.

Now turning to FIG. 2, there is shown a block diagram of an ASN gatewayor server 120 within the ASN 102 or the ASN 104 in accordance with thepresent disclosure. The gateway 120 includes a processor (which mayinclude a digital signal processor) 200, a memory 202, a transceiver204, input/output devices 206, and an antenna 208. Other components maybe included, but are not shown. Details of the operation and structureof these components, except as necessary to illustrate the operationsand methods described herein, have been omitted. The gateway includes ascheduler 210. Though shown as a separate component, the scheduler 210is normally a software process (or logical entity) that controls andmanages scheduling of data.

Now turning to FIG. 3, exemplary BTS 106 (and BTSs 108, 110, 112, 114and 116) is a medium to high-power multi-channel, two-way radio in afixed location. Such BTSs are typically provided for communication withsubscriber stations in the form of relatively low-power, single-channel,two-way radios or wireless devices such as mobile phones, portablephones, wireless computer networking cards (such as PCM/CIA and otherwireless connectivity devices) and wireless routers. The BTS 106 maycomprise a signal controller 300 that is coupled to a transmitter 302and a receiver 304. The transmitter 302 and the receiver 304 (orcombined transceiver) may further be coupled to an antenna 306. In theBTS 106, digital signals are processed in channel processing circuitry308 and the digital signals may be signals for a wireless communicationsystem, such as signals that convey voice or data intended for a mobileterminal (not shown). The signal controller 300 sends the digitalsignals to the transmitter 302 which includes the channel processingcircuitry 308 that encodes each digital signal and a radio frequency(RF) generator 310 that modulates the encoded signals onto an RF signal.The resulting RF output signal is transmitted over the antenna 306 to asubscriber station (not shown).

In addition, the antenna 306 also receives signals sent to the BTS 106from subscriber stations. The antenna 306 couples the received signalsto the receiver 304 that demodulates them into digital signals andtransmits them to the signal controller 300 and relayed to an associatedgateway 120. The BTS 106 may also include auxiliary equipment such ascooling fans or air exchangers for the removal of heat from the BTS 106.As will be understood by those skilled in the art, the BTS 106 mayemploy any suitable wireless technologies or standards such as 2G, 2.5G,3G, GSM, IMT-2000, UMTS, iDEN, GPRS, 1×EV-DO, EDGE, DECT, PDC, TDMA,FDMA, CDMA, W-CDMA, LTE, TD-CDMA, TD-SCDMA, GMSK, OFDM, WiMAX, thefamily of IEEE 802.11 standards, the family of IEEE 802.16 standards,IEEE 802.20 and the like, and can be used in a variety of applications,including cellular, WLAN, MAN and Femtocell communications networks.

FIG. 4 is a simplified diagram of communication paths and messagesbetween the BTS 110, the BTS 112, the ASN 102, and the ASN 104 in aWiMAX compliant network. With concurrent reference to FIGS. 1 and 4, theBTS 110 exchanges information with the gateway 12 (Y1) within ASN 102and the BTS 112 exchanges information with the gateway 120 (X1) withinASN 104. Each of these communication paths is referred to as an “R6interface” (as defined in the WiMAX standard). The ASN 102 and the ASN104 exchange information over an “R4 interface” (as defined in the WiMAXstandard). Though these paths are described as the R6 and R4 interfacesin accordance with WiMAX, other communication protocols or standards maybe utilized. It is explicitly understood that the ASN 102 and the ASN104 may each include one or more gateways 120, routers, servers, andother communication devices that make up an autonomous system.Communications over these paths and interfaces may include informationas shown in FIG. 5.

FIG. 5 is a chart 500 that describes information elements (IE), statusof those elements (e.g., M for mandatory and O for optional), and notesdescribing the contents of each element comprised within trafficexchanged by BTSs and ASNs. The information includes IEs 510, 520, 530,540, and 550. The IE 510 includes BTS location::latitude informationwhile the IE 520 includes BTS location::longitude information. The IE530 includes BTS coverage range information (range in meters). Inaddition, the IE 540 includes BTS antenna center angle directioninformation (direction antenna associated with the BS is pointing) whilethe IE 550 includes BTS antenna coverage angle information (angle overwhich the antenna associated with the BS can receive and transmit RFsignals). The information exchanged between BTSs and ASNs may furtherinclude (not shown): IP address of each BTS (IP Address), a unique BTSidentifier (BTS ID), preamble index and center frequency.

As will be appreciated, a given BTS may include one or more “sectors”.Conventional BTSs generally include three or six sectors (approximately120 or 60 degrees each) and therefore, may be described as includingthree or possibly six sectors. Therefore, each sector within a BTS has aset of IEs that can be utilized to describe it. As will be appreciated,some information, such as location, is typically the same for eachsector within a given BTS (e.g., each sector would have the samelocation information) while other information, such as coverage range,antenna coverage angle, and antenna center direction parameters, couldbe different.

It will be understood that each IE 510, 520, 530, 540 and 550 may betransmitted in separate packets or messages, or two or more IEs may betransmitted collectively within a single packet or message. Though notshown, each packet or message will typically include an identificationfield that identifies the included data as latitude, longitude, coveragerange, or antenna angle information. In one embodiment, the BTSlocation::latitude information and BTS location::longitude informationeach includes four octets (32 bits) of data representing degrees,minutes, seconds as integer values. The BTS coverage range informationmay be provided using four octets (32 bits) in a single integer denotingthe range in meters. The BTS antenna center direction information andthe BTS antenna coverage angle information may be provide using at totalof four octets (32 bits) with two integer values (alternatively, eachparameter could be transmitted separately). For each of the above, all0's may be used to represent an unknown status.

It is understood that these packets or messages will be used withincommunications between BTSs and their associated ASNs (or gateways) andalso between ASNs using the communication paths R6 and R4, respectively,as more fully described below.

Moving from the hardware and information elements described above usedto implement the disclosed systems and methods, one method of performingautomatic identification and learning of base station neighbors isillustrated in FIG. 6.

As previously described, BTS neighbor determination in a conventionalwireless network is provisioned manually. This approach requires a BTSneighbor list to be provisioned for each BTS and a change to BTSneighbor lists when the BTS topology changes (BTS added or removed).Further, there is no method to update neighbor lists based on BTSoperational status (up/down).

In accordance with the present disclosure, automatic determination ofBTS neighbor lists provides significant advantages over prior artprovisioning methods. As the network topology or operating conditionschange, BTS neighbor lists can be generated and/or updated automaticallyand dynamically (e.g. periodically or event-based driven).

In general terms, the present disclosure provides a method of generatingneighbor lists when there is a change in the number and/or operationalstatus of BTSs within the system 100. The neighbor list provides thegiven BTS with knowledge of its neighboring BTSs. Neighbor lists allowsBTSs to proactively avoid interruptions in service by handing subscriberstation communications off to a neighbor BTS when there arecommunication problems or for the purpose of balance BTS loads duringtimes of high demands (e.g., where a first BTS and second BTS areneighbors, if the first BTS has a very high usage, and the second BTShas a low usage, the first BTS can hand over all or a portion of itsongoing call sessions to the second BTS). In the instance of a newlyadded BTS to the system, the newly added BTS transmits its configurationparameters (IEs) (e.g., one or more of location, coverage range, antennadirection and coverage angle, IP address, BTS ID, preamble index andcenter frequency) to its associated gateway 120 within a respective ASN.After collecting this information, the gateway 120 propagates some orall of this information to peer gateway(s) 120 within the system 100.The gateway(s) 120 utilize the received BTS attributes, such as IEs,(received from its own BTSs and the other gateways 120) and generate BTSneighbor lists for the added BTS and any BTSs associated with it (i.e.,having overlapping coverages). The gateway(s) 120 then send the BTSneighbor lists to the newly added BTS and its associated BTSs.

It is expressly understood that a neighbor list may be created by anymember of system 100. In some embodiments, each gateway may create aneighbor list for each BTS in communication with the gateway. In otherembodiments, a single gateway will create a neighbor list for each BTSin system 100. In yet other embodiments, each BTS may have sufficientinformation sent to the BTS through a gateway to allow for the creationof its own neighbor list. These neighbor lists allow for the handoff ofcommunications from one BTS to another BTS, according to the neighborlist.

In another method, BTS neighbor lists may be dynamically updatedperiodically to take into account network operating conditions. This maybe done globally or within a specified region of the network. In yetanother method, BTS neighbor lists may be dynamically updated inresponse to a change in network operating conditions. Similarly, thismay be performed on a global basis, regionally, or at or around a givenBTS. In either method, the gateway(s) 120 collect the BTS configurationparameters and information, generate neighbor lists, and propagate theneighbor lists to its associated BTSs. This allows for dynamic tuning,enhancement and optimization of BTS neighbor lists. FIG. 6 illustrates amethod 1000 of creating a neighbor list for a given BTS. In this method,configuration parameters (such as Information Elements (IEs”) or otherinformation concerning a given BTS (such as BTS 112) is determined (step1002) and transmitted to its associated gateway (such as gateway120(X1)) (step 1004). Such determination can be undertaken by one orboth of the BTS and associated gateway 120. The gateway 120 (X1)generates a neighbor list on the basis (at least in part) of thetransmitted received BTS configuration parameter information and BTSconfiguration parameter information of other BTSs, such as BTS 110 (step1006). The BTS configuration parameter information of the other BTSsis/was obtained directly from the BTSs or via their associated gateways,such as gateway 120(Y1). In an optional step, the generated neighborlist may be optimized (step 1008) through a single or iterative process.The generated BTS neighbor list is sent to the BTS 112.

The above described method 100 illustrates the generation of theneighbor list for a single BTS 112. It will be understood that themethod may be performed for additional BTSs, where each gateway 120retrieves BTS configuration parameter information from each BTS itmanages, each gateway 120 sends this information to the other gateways120, each gateway 120 creates neighbor lists and sends a respective listto each managed BTSs.

In one embodiment, BTS neighbor list generation may occur withoutantenna direction and coverage angle information, and utilizes BTSlocation and coverage range information. This approach considers the BTScoverage area as a circle defined by the BTS location and coveragerange. Two BTSs are defined as neighbors if their coverage areas areintersecting circles. In another embodiment, BTS neighbor listgeneration further utilizes antenna direction and coverage angleinformation. This approach considers the BTS coverage area as a convexpolygon defined by the BTS location, coverage range and antennadirection and coverage angle information. Two BTSs are defined asneighbors if their coverage areas are intersecting polygons. It isunderstood that elements from both embodiments might be used together,and these embodiments are presented solely for the purpose in aiding inunderstanding the present disclosure.

In a first embodiment, the gateway 120(Y1) receives the followinginformation directly from the BTS 110:

BTS 110:

-   -   Longitude (in radians): LONGa    -   Latitude (in radians): LATa    -   Coverage range (in km): Ra        and also receives the same type of information from BTS 106 and        BTS 108. The gateway 120(Y1) propagates this information to the        gateway 120(X1). Similarly, BTS the gateway 120(X1) receives the        following information directly from the BTS 112:

BTS 112:

-   -   Longitude (in radians): LONGb    -   Latitude (in radians): LATb    -   Coverage range (in km): Rb        and also receives the same type of information from BTS 114 and        BTS 116. The gateway 120 (X1) similarly propagates this        information to the gateway 120(Y1). In one aspect of the        invention, each gateway 120 uses equation (1) below to determine        whether any pair of BTSs are neighbors (if the inequality is        true, the base stations are neighbors, if it is false they are        not):

DISTANCE(BSa, BSb)<Ra+Rb  (1)

where DISTANCE (BSa, BSb) is defined by Equation (2) below:

DISTANCE(BSa,BSb)=cos(cos(LONGa)*cos(LATa)*cos(LONGb)*cos(LATb)+cos(LONGa)*sin(LATa)*cos(LONGb)*sin(LATb)+sin(LONGa)*sin(LONGb))*6378  (2)

In the example illustrated in FIG. 1 and described above, BTS 110 andBTS 112 are neighbors.

This approach is useful when looking at a plurality of BTS stations.FIG. 7 shows a plurality of BTSs 1102, 1104, 1106, 1108, 1110, and 1112.Using Equation (1) the following neighbor list may be created:

-   -   BTS: Neighbors    -   1102: 1104    -   1104: 1102, 1106, 1110    -   1106: 1104, 1108    -   1108: 1110, 1106    -   1110: 1104, 1108, 1102    -   1112: 1110

It is explicitly understood that any or all of the BTS may be connectedto separate ASNs.

The first embodiment is useful in the initial configuration of thesystem 100 or when network operating conditions affect one or more BTScoverage ranges. When BTS coverage ranges change due to operatingconditions and the BTS (or its managing gateway) has functionality tocalculate its own BTS coverage range, the first embodiment may beutilized to dynamically tune or update the neighbor list(s). BTScoverage range may be calculated based on any factors that may affectrange, including power level, receiver sensitivity, modulationefficiency (no variation with frequency), shadow margin, path loss,physical environment, and cable loss (variation with frequency). Asnoted above, this technique may be done periodically (whether or not anyBTS coverage ranges have been detected as having changed) or in directresponse to a coverage range detection. The network 100 may initiate aperiodic neighbor list update process that causes each BTS (or itsassociated gateway) to calculate its coverage area and transmit it(along with its location) to the gateways (which then generate updatedor dynamically tuned neighbor lists).

It will be understood that additional information about BTSconfigurations may be useful in tuning and optimizing the network. Forinstance, further information may be gathered and used including, butnot limited to, antenna direction angle, antenna coverage angle, powerlevel, receiver sensitivity, modulation efficiency (no variation withfrequency), shadow margin, path loss, physical environment, cable loss(variation with frequency) with location and range information. Thisinformation may be used to determine range of the BTS.

FIG. 8 is an example showing a BTS 1200 at the center with a pluralityof antenna center angles within a coverage area. As shown by FIG. 8there may be a plurality of antenna center angles (created by aplurality of antennas located on the BTS) present within the coveragerange of the BTS 1200. This figure also shows a plurality of sectorsshown within the coverage range.

By intelligently determining and using sector information, a number offactors may be determined. For instance, location within the coveragearea may be blocked by a physical barrier to a signal that renders asubscriber station unable to communicate with the BTS 1200 even thoughthe subscriber station is located within the range of the BTS 1200.Through tracking of dropped calls or loss of signal to the BTS 1200, theBTS 1200 can determine that an impediment exists in a particular sectorand adjust the coverage range that it transmits to the gateway 120 forthat sector. Through this intelligent determination of sectorinformation, the true range and capability of the BTS 1200 can bedetermined. When a subscriber station enters a sector where there issuch an impediment, the BTS 1200 checks the neighbor list to determineif there is a suitable neighbor BTS for handoff of the communication.Therefore, the neighbor list promotes maintenance of communicationssessions between mobile devices and BTSs.

FIG. 9 illustrates an overlap of a sector from a BTS 1302 and a sectorfrom a BTS 1304. As shown, the range and coverage angle may be used todetermine the area in which the BTS has effective coverage. The BTS 1302and the BTS 1304 also are shown to have a limited area of overlap.Through the identification of this overlap, the location and timing ofhandoffs between the BTS 1302 and the BTS 1304 may be determined andoptimized prior to a subscriber station entering the coverage area. Thistype of novel tuning, that exists prior to any real MS entering thecoverage area of the BTS 1302 or the BTS 1304, allows for theoptimization of a network based upon the plurality of factors abovewithout the need to manually tune a network (i.e., manually adjust theneighbor lists). In addition, it can be identified where a BTS has noeffective coverage simply by determining areas where signal lossesconsistently occur.

The BTS 1302 and the BTS 1304 are neighbors only for some of the sectorsthat are present within the BTS 1302 and the BTS 1304. In the morecomplex model, a list can be generated that includes both the BTS andthe sector of the BTS that is a neighbor of another BTS:

-   -   BTS: Neighbors (SECTOR)    -   1302: 1304(4)    -   1304: 1302(2)

The information obtained through the methods described in the morecomplex model may be used to tune and optimize the network. Asillustrated by FIG. 6, the tuning and optimizing of the network may beperformed through an iterative process that allows for constant retuningand updating based upon the actual capabilities of each BTS within thenetwork. FIG. 10 is an example of the neighbor list that may begenerated by a gateway 120.

In the example shown in FIG. 10, blocks 1402 are a list of the BTSswithin the network 100. Blocks 1404 relate to the relative weight ofeach BTS for communication with a first BTS. Blocks 1406 relate to therelative weight of each base station for communication with a secondBTS. For instance, using the example shown in FIG. 11, the blocks in1402 might appear as 1102, 1104, 1106, 1108, 1110, and 1112. The weightsfor block 1104 might be 1102 (50), 1106 (30), and 1110 (20). Therefore,BTS 1102 has the highest communication priority with BTS 1104. As isshown by FIG. 6, each BTS has its own neighbor list and priority list.This priority list could further be expanded to consider the sector forwhich the transmission is in. In such a case, blocks 1404 would includeBTS sector information as well as weights. For example, the followinglist could be used using the example from FIG. 9:

-   -   BTS (SECTOR): Neighbors (SECTOR), Weight    -   1302(1): 1104, 50    -   1302(2): 1104, 0

Even though BTS 1302 and BTS 1304 are neighbors, it does not follow thatevery sector of BTS 1302 is within the range of every sector within BTS1304. Through the more complex method, a precise sector-to-sectorneighbor list may be created.

The neighbor list and weights of the neighbor list may be createdthrough a plurality of messages from both gateways 120 and BTSs. Onemethod of creating weights is by incrementing the weight of the BTSbased upon successful or unsuccessful communication. In this example, ifa subscriber station has a successful communication session with theBTS, the weight of the BTS may be increased. If the communication withthe BTS was unsuccessful, the weight of the BTS may be decreased.

The neighbor list, and weights of the neighbor list, may also be createdthrough a plurality of messages from the ASN 102 and the BTS 114. In oneexample, a mobile station is within the range of the BTS 110 and the BTS114 and the mobile station transmits a list of all BTSs within the rangeof the mobile station to BTS 110. This information is then relayed tothe ASN 102 through BTS 110. A HO_Req message may then be sent from BTS110 comprising the list of target candidate BTSs seen by the mobilestation to other BTSs, including BTS 114. This candidate list can beused as feedback to dynamically tune the BTS 114 at runtime, byproviding the BTS 114 a list of BTSs that the mobile station is awareof. It may be assumed if the mobile station is aware of a plurality ofBTSs, each of the BTSs must share at least some coverage area (e.g., inthis example, the BTS 110 and the BTS 114 would share some coveragearea). The ASN 102 may also send a HO_Cnf message that comprises a listof all BTSs for a mobile station that are within the range of the mobilestation to all of the BTSs within the range of the mobile station. It isunderstood that the HO_Req and Ho_Cnf are R6 messages which can be sentfrom the BTS to the ASN.

In addition to the BTS 110 sending the list of target BTSs seen by themobile station to the ASN 102, the mobile device may send a MOS_MSHO_REQmessage with a list of target BTSs identified by the mobile devices toother BTSs within the range of the mobile device (e.g. BTS 114). Themobile device may also send an individual message, MOS_MSHO_IND, to theBTS that has been selected for communication with the mobile device. Ifthe target BTS reports successful communication or handoff, the weightsof the BTS may be adjust accordingly. Therefore, these messages may beused to determine the weight for each BTS to communicate with anotherBTS. It is understood that the MOS_MSHO_REQ and MOS_MSHO_IND aremessages sent from the mobile device to the BTS. Messages that are sentbetween a mobile device and a BTS may be referred to as R1 messages.

The neighbor list, and weights of the neighbor list, may also be createdthrough a plurality of messages from the ASN 102 and the BTS 114. In oneexample, a mobile station is within the range of the BTS 110 and the BTS114 and the mobile station transmits a list of all BTSs within the rangeof the mobile station to BTS 110. This information is then relayed tothe ASN 102 through BTS 110. A HO_Req message may then be sent from ASN102 comprising the list of target candidate BTSs seen by the mobilestation to other BTSs, including BTS 114. This candidate list can beused as feedback to dynamically tune the BTS 114 at runtime, byproviding the BTS 114 a list of BTSs that the mobile station is awareof. It may be assumed if the mobile station is aware of a plurality ofBTSs, each of the BTSs must share at least some coverage area (e.g., inthis example, the BTS 110 and the BTS 114 would share some coveragearea). The ASN 102 may also send a HO_Cnf message that comprises a listof all BTSs for a mobile station that are within the range of the mobilestation to all of the BTSs within the range of the mobile station.

In addition to the BTS 110 sending the list of target BTSs seen by themobile station to the ASN 102, the BTS 110 may send a MOS_MSHO_REQmessage with a list of target BTSs identified by the mobile devices toother BTSs within the range of the mobile device (e.g. BTS 114). BTS 110may also send an individual message, MOS_MSHO_IND, to the BTS that hasbeen selected for communication with the mobile device. If the targetBTS reports successful communication or handoff, the weights of the BTSmay be adjust accordingly. Therefore, these messages may be used todetermine the weight for each BTS to communicate with another BTS.

In some embodiments, some or all of the functions or processes of theone or more of the devices are implemented or supported by a computerprogram that is formed from computer readable program code and that isembodied in a computer readable medium. The phrase “computer readableprogram code” includes any type of computer code, including source code,object code, and executable code. The phrase “computer readable medium”includes any type of medium capable of being accessed by a computer,such as read only memory (ROM), random access memory (RAM), a hard diskdrive, a compact disc (CD), a digital video disc (DVD), or any othertype of memory.

It may be advantageous to set forth definitions of certain words andphrases used throughout this patent document. The terms “include” and“comprise,” as well as derivatives thereof, mean inclusion withoutlimitation. The term “or” is inclusive, meaning and/or. The phrases“associated with” and “associated therewith,” as well as derivativesthereof, mean to include, be included within, interconnect with,contain, be contained within, connect to or with, couple to or with, becommunicable with, cooperate with, interleave, juxtapose, be proximateto, be bound to or with, have, have a property of, or the like. Whilethis disclosure has described certain embodiments and generallyassociated methods, alterations and permutations of these embodimentsand methods will be apparent to those skilled in the art. Accordingly,the above description of example embodiments does not define orconstrain this disclosure. Other changes, substitutions, and alterationsare also possible without departing from the spirit and scope of thisdisclosure, as defined by the following claims.

1. A method, comprising: determining a local node configuration for alocal network node, wherein the local network node configurationcomprises a local range and a local location; receiving via acommunications link a remote network node configuration for a remotenetwork node, wherein the remote network node configuration comprises aremote range and a remote location; and generating a neighbor listcomprising the remote network node and the local network node, whereinthe neighbor list is determined using the local network nodeconfiguration and the remote network node configuration.
 2. The methodof claim 1, wherein the node configurations further comprises sectorinformation.
 3. The method of claim 1, wherein the neighbor listcomprises the angles in which the local network node is a neighbor to aremote network node.
 4. The method of claim 1, wherein the local networknode is a base transceiver station.
 5. The method of claim 1, furthercomprising updating the network list based upon usage information. 6.The method of claim 1, wherein the local network node is configured touse data including the signal strength from mobile stations to determinethe range of the local network node.
 7. A method, comprising: obtaininga first information about a first base station, wherein the firstinformation comprises location and range information relating to thefirst base station; sending the first information to a first server;obtaining a second information about a second base station, wherein thesecond information comprises location and range information relating tothe second base station; sending the second information about the secondbase station to the server; generating a neighbor list from the firstinformation and the second information; transmitting the neighbor listto the first base station and the second base station; and storing theneighbor list in the first base station and the second base station. 8.The method of claim 7, wherein the first information further comprisesinformation related to the signal strength of the first base station. 9.The method of claim 8, further comprising updating the neighbor listbased upon usage information.
 10. The method of claim 7, wherein thefirst information further comprises angle information.
 11. The method ofclaim 7, wherein the first information further comprises transmissionpower information of the first base station.
 12. The method of claim 9,further comprising handing off communication between a mobile stationfrom the first base station to the second base station based upon theneighbor list.
 13. The method of claim 7, wherein the sending of thefirst wireless communication is preformed through a wirelesscommunication channel.
 14. The method of claim 7, wherein the server ispart of a packet switched network.
 15. The method of claim 14, whereinthe server is a gateway.
 16. The method of claim 7, further comprising asecond server, wherein the server transmits the neighbor list to thefirst base station, and the second server transmits the neighbor list tothe second base station.
 17. The method of claim 16, wherein the handoffis based upon sector information.
 18. A system, comprising: a first basestation, wherein the first base station is capable of storing firstidentification information relating to the range of the first basestation and the location of the first base station, and wherein thefirst base station is capable of communication with a first network; asecond base station, wherein the second base station is capable ofstoring second identification information relating to the range of thesecond base station and the location of the second base station, andwherein the second base station is capable of communication with asecond network; a server, wherein the first server is capable ofcommunication with the first network and the second network, and whereinthe server is capable of receiving the first and second identificationinformation, creating a neighbor list based upon the first and thesecond identification information, and transmitting the neighbor list tothe first base station and the second base station.
 19. The system ofclaim 18, wherein the first base station unit further stores angleinformation relating the first base station coverage angle.
 20. Thesystem of claim 18, wherein the first base station unit further storesdirection information relating the first base station centre angle.